The system of traffic roundabout system has been part of the United States technology since 1905. The main purpose of the roundabout is to enable the entry of weaving and merging of vehicles. This purpose has been performed through basic design procedures but during the 1950’s problems like vehicular incidents and the traffic congestion are on its highest number.
In 1966, development of roundabout design was initiated by the United Kingdom through a policy known as “give-way” traffic. This rule obliged entering traffic to give way, yield or stop to circulating or flowing traffic.This was the beginning of the modern roundabout which was adopted in the United States to solve the traffic problems entailed by the original design. These modern roundabouts give a significant development in terms of safety and operation.
With these improvements in the design and rules to be followed in the roundabout system, many countries have persuaded to use this system of transportation and also work for their own design and methods. In lieu with this, basic design criteria that have been evaluated by many transportation experts should be always present.All roundabout designs should always be under the two-step procedure: a preliminary design meeting all the general and specific criteria; and the final design which includes the proper materials and construction marking. The general design criteria include appropriate roadway location, approach and circulatory speeds, pedestrian, design vehicles, utilities and drainage, and landscaping. On the other hand, specific design includes the approach roadway, circulating roadway, sight distance, central island, signing and marking, splitter island, and the landscaping elements.